Question: Can I use my maaser money for matanos laevyonim and kimcha depischa?Answer: While there is a clear mitzva deoraisa to give tzedaka, there is a machlokes as to whether giving maaser (10% of one’s earnings) is deoraisa, derabannan, or just a minhag. Tosafos (Taanis 9a) writes that maaser is deoraisa and Maharil (54) writes that it is derabannan though most poskim (Bach YD 331; Chavos Yair 224; Shaalos Yaavetz 1:3) maintain that it is a laudable minhag. (See Aruch Hashulchan YD 249:5; Tzitz Eliezer 9:1). Thus, the Chafetz Chaim (Ahavas Chesed 18:2) advises one to stipulate that they are giving maaser, ‘bli neder’.
Based on this, there is a machlokes as to what one may use his maaser money for. The Rema (YD 249:1) writes that it may only be used to support the poor and not for any other mitzva, while the Shach (YD 249:1) quotes the Maharam who allows one to use one’s maaser for a mitzva that one would not have otherwise paid for.
The Chasam Sofer (YD 231) explains that if one initially intends to use one’s maaser for other charitable causes or mitzva expenditures, then one may do so. This does not apply to mitzvos that one is obligated to do, such as buying a lulav and esrog. Thus, one may not use one’s maaser for machatzis hashekel or matanos laevyonim. The Magen Avraham (OC 694:1) and Mishna Berura (694:3) write that once one has fulfilled the basic mitzva (by giving 2 coins to 2 people, Mishna Berura 694:2) one may continue distributing money from one’s maaser.
As there is no fixed amount to give to for kimcha depischa (money to assist others in additional Pesach expenses) one may use one’s maaser for this.